Process for preparing 4-chlorobenzyl propargyl ether

A process for preparing a compound of formula I

• comprising a step (a) of reacting a compound formula II
• with a compound of formula III
• in the presence of a base and a phase transfer catalyst in a reaction mixture,
• wherein the reaction mixture comprises at least two phases, wherein one phase is an organic phase and one phase is an aqueous phase,
• wherein the base is selected from the group consisting of alkali metal and alkaline earth metal hydroxides, alkali metal and alkaline earth metal oxides, alkali metal and alkaline earth metal carbonates, alkali metal and alkaline earth metal hydrogen carbonates, alkali metal and alkaline earth metal alcoholates, a tertiary amine, a pyridine, a bicyclic amine, and mixtures thereof, and
• wherein the phase transfer catalyst is selected from the group consisting of benzyltrimethylammonioum chloride, tetraethylammonium chloride, tetrapropylammonium bromide, tetrabutylammonium bromide, and tributylmethylammonium chloride,
• wherein the process further comprises
• (b) adding an organic solvent and/or water to the mixture obtained in the reaction step (a),
• (c) separating the at least two phases of the mixture obtained in step (b), and
• (f) isolating the compound of formula I from the organic phase obtained in step (c),
• wherein the phase separation step (c) comprises the separation of three phases,
• wherein one phase is an organic phase, one phase is an aqueous phase, and one phase is a catalyst-containing phase,
• wherein the process further comprises isolating the catalyst-containing phase.